In the private and secretive world of online insemination there's a special category called natural -- dissemination or in nine. In other words having sex with people you meet online specifically. To get pregnant. At least it. Third of women. -- that there are available for an ally as an option how many actually go through -- I don't know. To understand -- some women would even consider that option you need to meet Tonya. -- -- to be a mom says Alice and child time his journey began when she was nineteen years old. I got pregnant -- and I just had -- place our child for adoption. It changed me forever act have a hole in my heart. Attack have that now their biological child sex -- he -- -- be Harmer. He would at least you. -- me feel little bit -- In her thirties Tonya had a longtime boyfriend but when he told her he didn't want children it crushed her heart but not her hope. She turned to sperm banks I unfortunately T. -- three miscarriages. Punishment -- Probably 67000. I didn't have any infertility insurance at all says I had to pay for everything -- -- pocket. This past summer after her third miscarriage she still longed for a child she went online. Tanya found the -- sperm donor registry and opted to leave the choice between artificial and natural insemination. -- But just decided that -- See if this person was someone that I would be interested in nearly -- -- this session. One online donor -- her interest. Spent -- he now -- talking on the and really getting to know each other. Eventually they agreed to meet on you found herself conducting the strangest interview she could imagine. Over dinner and a glass of wine. Whereabouts shaking as we were -- our plan -- that had he done this before not an uproar recently. And now it's hard to completely dogged pursuit of al-Qaeda -- -- that I. Apparently. -- -- aren't the way he brings it to me he genuinely wanted to help someone. What kinds of questions did you ask. We actually started from the very beginning from rich culture and you are it's funny and college. Towns -- to -- For unless. It actually turned out to be -- day. It did it won't really -- -- hit the jackpot in fact she says they began to sleep together. Anybody -- and red flag saying this isn't a good idea. Definitely -- today. So to people who think it's crazy he would say. I thought it was crazy. -- -- team but we'll have one thing and and they have eighty all the -- I'm needed -- waste inch long time have come together are commonly. Do you have like yours. Two action. Being a mom took action this time holding your baby and keeping him or her. -- hope that -- teacher. I definitely do. But for every hopeful novice like Tonya and dabbling on the web there is someone like this man but appetite you have sex zones. We'll call him Joseph and he asked that we disguise his face and his voice because he is a secret online life. He says he -- women often in hotel rooms who have sex with him because they believed in natural insemination. Increases their chances of getting pregnant. How many children total to -- Burton or at least it. And -- -- he also has three kids and a white at home does your wife and I are doing just -- We'll have that begs the question that there was something wrong -- keep it a secret. Just. -- as people do what they wanted to do. And birds and -- also. Right that people want to have sex with other people sometimes it's called extramarital affairs go to -- interest this could lead to progress. Joseph says he's been doing this for three years and it's great satisfaction from impregnated women. He says he provides STD test results if the women ask for them. Why this need to have more kids a lot of people understand. A similar people to reduce some people already go through -- -- stories more. This -- some like you know. Man thing I -- can help me understand. And it's just something there -- -- it is important. Change summit that what you're doing is altruistic. It's what his prewar apartments occurrence -- with -- Are -- so it's not altruistic you're doing this for yourself. We got a Sunoco a win win situation. And you don't think what you're doing is the kind of creepy -- anyway. Will -- -- people were rebels who are smoother open through the sort of we want that to happen. Three men each pursuing an online mission to procreate and and three women on a personal quest to have a baby by any means possible. -- tells -- she is still dating and -- also look into adopting. -- who got pregnant with Trent but missed -- soon after -- that despite revelations about his pornographic postings she still believes in him. As a donor and they may try again. I actually -- had no second thoughts with trend there's a lot of risk involved there's a lot of unknowns he -- right choice -- I know that I will be a mother someday I just don't know how yet. And remember Beth and her husband Richard. After they inseminated withdrew a -- Maryland hotel room she did not get pregnant but she and drew are trying again. I was really starters that I want to to child I have to work extra to get it. I don't give them. So what's better fresh or frozen. See more of the debate at our website at abcnews.com. Slash 20/20.

This transcript has been automatically generated and may not be 100% accurate.

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